and certification, difficulties in setting up a Canadian subsidiary and revenue lost due to the certification delays. It had lost almost £10 million between June 1978 and September 1983, and its share price fell from a 1983 high of 147p to 56p in March 1984. However, AI reported its first profit, some £50,000, in the 15 months to 30 June 1985. The Sentinel 5000/YEZ-2A programme In February 1985, the United States Navy (USN) issued a request for proposal for a radar-carrying Battle Surveillance Airship System (BSAS). AI responded with the Skyship 5000, "a concept airship of about " The BSAS programme was subsequently renamed the Naval Airship Surveillance Program (NASP), then the Organic Long Endurance Airborne Area Surveillance Airship System, and finally became the Naval Airship Program. In mid-1985, the Naval Air Development Center awarded three six-month contracts for further studies to, respectively, Goodyear Aerospace, Boeing paired with Wren Skyships, and Westinghouse paired with AI. The Navy was reported to be "interested in up to 75 airships." On 5 June 1987, Westinghouse–Airship Industries (WAI) won the contract to build an Operational Development Model (ODM), or prototype, with the possibility of a production run of 40–50 airships if the ODM proved successful in trials. However, NASP was cut from the fiscal year 1989 defence budget. Congress later authorised funding to continue the ODM's development, and the Defense Advanced Research Projects Agency inherited the programme from the Navy. In the design proposed in 1989, the Sentinel 5000, designated the YEZ-2A by the Navy, would have been long and in diameter, containing of helium. A crew of 10–15 would have been accommodated in a triple-decked, partly pressurised gondola, on top of which (within the envelope) the radar antenna was to be mounted. The ship would have been powered by two CRM diesel engines, with a supplementary General Electric T700 turboprop for "dash" situations. It would have offered an unrefuelled endurance of two to three days, which could be extended to 30 days through refuelling and replenishment from surface ships. AI produced a smaller airship, the Sentinel 1000, as part of the development programme. The 1000 was a half-linear-scale model of the 5000, having a modified Skyship 600 gondola but a larger () envelope and an empennage resembling the "X" form planned for the 5000, rather than the cruciform one of the 600. Other features included fly-by-light controls, an envelope material that eliminated the